Service processors attached to computers are more and more frequently used for initialization, incident recording and maintenance purposes.
A description of such an arrangement of a service processor and a computer system may be found in U.S. Pat. No. 4,268,902 assigned to the same assignee, filed on Oct. 23, 1978, and entitled "Maintenance interface for a service processor-central processing unit computer system".
The Communications Controller IBM 3725 is also provided with a service processor.
In such a controller, only a fraction of the microcode malfunctions leading to an unoperational state of the service processor is detected, the hardware failures which also lead to an unoperational state of the processor are never explicitly detected. As this controller may be part of a system such as a telecommunication network, detecting the unavailability of the service processor is a key factor for the reliability of the whole system, specially the telecommunication network. An object of the invention is a device which allows any kind of failure : i.e. microcode and hardware failures occurring in a processor to be detected as soon as possible.
Another object of this invention is to provide such a device which is simple and requires only little additional hardware